Generally, a hair cosmetic composition used for dyeing, bleaching, or destaining hair contains an alkaline agent and an oxidizing agent. The oxidizing agent acts to remove melanin from hair. The alkaline agent acts to improve lightness of bleached hair by promoting the action of the oxidizing agent. When a hair cosmetic composition contains a dye, the alkaline agent also acts to improve the dyeability of hair by swelling hair so as to improve the permeability of the dye into the hair. Accordingly, lightness of the hair treated with a hair cosmetic composition can be improved by increasing the amounts of an alkaline agent and an oxidizing agent added to the hair cosmetic composition. Conventionally, ammonia and alkanolamine are commonly used as an alkaline agent in a hair cosmetic composition. However, a problem has been that pungent odor is produced when the amount of ammonia added is increased. Also, there has been a risk that, when the amount of alkanolamine added is increased, alkanolamine remaining on the hair after washing could cause irritation to the scalp.
Patent Document 1 discloses a hair bleach composition containing a water-soluble polymer compound, a higher alcohol, and an ester of a branched-chain fatty acid. The hair bleach composition of Patent Document 1 is intended to achieve both increasing lightness of the treated hair and reducing the production of pungent odor.